Dog Age ToolsHow do you read a dog years chart?
Find the dog's age in the first column, then move across to its size. A 7 year old dog is about 44 in human years if it is small, 47 if medium, 50 if large and 56 if giant. The last column uses the UCSD DNA formula, which gives about 62 for any size.
The size columns follow the guide used by the AKC, based on the AVMA. Year one is 15, year two brings the total to 24, and later years add about 4 to 6 depending on size. The DNA column uses the formula 16 × ln(age) + 31 from a 2020 study in Cell Systems.
Puppy months to human years
Puppies age fastest of all. This table covers the first 18 months.
| Dog age | Medium size chart | DNA clock |
|---|---|---|
| 2 months | 2.5 | 2.3 |
| 3 months | 3.8 | 8.8 |
| 4 months | 5 | 13.4 |
| 6 months | 7.5 | 19.9 |
| 9 months | 11.3 | 26.4 |
| 12 months | 15 | 31 |
| 18 months | 19.5 | 37.5 |
The two methods disagree most in the first year. The size chart moves in a straight line from 0 to 15. The DNA clock rises fast, so a 6 month old pup is about 20 by its DNA. In the study, 8 weeks matched about 9 months in a human baby.
When does each size become a senior?
The AVMA puts senior age at the last quarter of expected life. That is about 8 to 11 years for small dogs, 8 to 10 for medium dogs, 8 to 9 for large dogs and 6 to 7 for giant breeds. Senior dogs should see a vet at least twice a year.
Read more in the AVMA senior pet guide.
Is the 7 year rule wrong?
Yes, for most of a dog's life. The AVMA says dogs do not age 7 human years per dog year. The rule makes a 1 year old dog only 7, yet a dog that age is already full grown. It also makes a 16 year old dog 112, far older than the chart above for any size but giant.
Breed lifespan and age charts
FAQ
How old is a 10 year old dog in human years?
About 56 for a small dog, 60 for a medium dog, 66 for a large dog and 79 for a giant dog, using the size chart. The DNA clock gives about 68 for any size.
Is a small dog age chart different from a large dog age chart?
Yes, after about age 5. Up to then, small, medium and large dogs follow nearly the same path. After that, large dogs add 5 to 6 human years per year, while small dogs add about 4.
Why does the giant column start lower?
Giant breeds grow for longer, so a 1 year old Great Dane is still maturing. The chart sets year one at 12 for giants. From year three on, giants age faster than every other size.
Can I print this chart?
Yes. Use your browser print button. The menu and footer are hidden in print so the chart fits on one page.
References
- Caring for senior cats and dogs, American Veterinary Medical Association
- How to Calculate Dog Years to Human Years, American Kennel Club
- Wang T. et al. (2020). Quantitative Translation of Dog to Human Aging by Conserved Remodeling of the DNA Methylome. Cell Systems 11(2)
- From dog days to human years, Nature Reviews Genetics research highlight (2020)